PURPOSE: To alternately regenerate cryopanels and permit the continuous operation by partitioning the inside of a pump case to a plurality of trap chambers by a cold head and arranging each cryopanel, heating means, and each exhaust means in each trap chamber.

CONSTITUTION: Cryopanels 35a and 35b arranged on a plurality of trap chambers 31a and 31b are cooled by cooling a cold head 34. An intake port of one trap chamber 31a is closed by one opening/closing means 30a, and one cryopanel 35a is heated by one heating means 36a, and the surface accumulated articles are gasified. Then, gas is discharged outside the trap chamber 31a by an exhaust means 37, and one cryopanel 35a ia regenerated. During the regeneration of one cryopanel 35a, the other cryopanel 35b arranged in the other trap chamber 31b condensation-solidifies the base body particles on the surface and makes the other trap chamber 31b vacuum.